Lifting clamp

ABSTRACT

In a preferred form, this disclosure relates to a releasable lifting clamp which comprises a hollow cylindrical body portion with a plurality of axially elongated, circumferentially spaced slots therein which terminate at one end in inclined surfaces. The clamp also includes a hollow cylindrical locking sleeve which is supported upon the body in a concentric manner for sliding movement thereon in opposite directions and which has a plurality of circumferentially spaced slots therein. A plurality of jaws which have tangs received within the slots of the locking sleeve are slidably received within the slots of the body portion for movement with the locking sleeve. The lifting clamp further includes a spring means which biases the jaws into engagement with the inclined surfaces. The locking sleeve when moved in first and second directions upon the body and against the bias of the spring means and with the bias of the spring means serves to expand and contract the jaws, respectively.

United States Patent [1 1 Kell i 1 LIFTING CLAMP [75] Inventor:Nathaniel B. Kell, Indianapolis,

Ind.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Oct. 5, 1971 [2]] Appl. No.: 186,627

.[52] US. Cl. 294/8631, 294/8633 [51] Int. Cl B25b 5/08 [58] Field ofSearch 294/115, 86.27, 86.28,

294/8629, 86.16, 86.17, 86.18, 86.19, 86 R, 83 R, 99 S, 100, 86.30,86.31, 86.26, 86.33,

Primary Examiner-Harvey G. Hornsby Assistant Examiner-James W. Miller Attorney- W. E. Finken and W. A. Schuetz July 3,1973

[57] ABSTRACT In a preferred form, this disclosure relates to areleasable lifting clamp which comprises a hollow cylindrical bodyportion with a plurality of axially elongated, circumferentially spacedslots therein which terminate at one end in inclined surfaces. The clampalso includes a hollow cylindrical locking sleeve which is supportedupon the body in a concentric manner for sliding movement thereon inopposite directions and which has a plurality of circumferentiallyspaced slots therein. A plurality of jaws which have tangs receivedwithin the slots of the locking sleeve are slidably received within theslots of the body portion for movement with the locking sleeve. Thelifting clamp further includes a spring means which biases the jaws intoengagement with the inclined surfaces. The locking sleeve when moved infirst and second directions upon the body and against the bias of thespring means and with the bias of the spring means serves to expand andcontract the jaws, respectively.

3 Claims, 4 Drawing Figures PATENTEDJUL3 ma 7 3753342 ATT R/VEY LIFTINGCLAMP The present invention relates to a lifting clamp, and moreparticularly to a releasable lifting clamp having jaws which can beexpanded and contracted to grasp and release other objects.

Clamps have heretofore been provided which include a plurality of jawswhich have certain portions cammed to expand or contract the jaws tograsp and release other objects. For telecentric see U.S. Pat. No.1,583,767. Lifting clamps have also been previously provided wherein thecontraction of the jaws occurs as a result of the sliding axial movementof a locking sleeve upon a body portion within which the jaws aremounted. For example, see U.S. Pat. No. 1,570,065. The aforementionedclamps are of a complex construction and have the disadvantage thatassembly and disassembly is difficult when it is necessary to replacebroken members, because mechanical fasteners, welding, staking, etc. areusually required for assembly.

Accordingly, an important object of the present invention is to providea new and improved releasable clamp which is of a simple and economicalconstruction, wherein mechanical fasteners, etc are not required forassembly and wherein any component of the lifting clamp can be easilyremoved and replaced.

Another object of the present invention is to provide a new and improvedreleasable lifting clamp comprising a hollow cylindrical body which hasa plurality of elongated, axially extending, and circumferentiallyspaced slots therein which terminate at one end in inclined camsurfaces, a hollow cylindrical locking sleeve which is supported uponthe body in a concentric manner for sliding movement thereon in oppositedirections and which has a plurality of circumferentially spaced slotstherein, a plurality of jaws having tangs received within the slots ofthe locking sleeve and which are slidably received within the slots ofthe body portion for movement with the locking sleeve, and a springmeans which biases the jaws radially outwardly into engagement with thecam surfaces, and said locking sleeve when moved in first and secondopposite directions against the bias and with the bias of the springmeans serving to expand and contract the jaws, respectively.

These and other objects of the invention are accomplished, in apreferred embodiment, by providing a lifting clamp which comprises ahollow cylindrical body having a plurality of axially extending andcircumferentially spaced slots therein which terminate at a positionadjacent one end of the body in inclined surfaces. The body has aradially outwardly extending'lip adjacent the one end of the body andalso has means attached to its other end for attaching the lifting clampto a lifting device. The lifting clamp also includes a hollowcylindrical locking sleeve which has one end engaging the lip of thebody and which is supported thereby in a con centric manner for slidingmovement upon the body between a forward and a retracted position. Thelocking sleeve also has a plurality of circumferentially spaced slotstherein. The lifting clamp further includes a plurality ofjaws whichhave tangs at their upper ends that are received within the slots of thelocking sleeve and which have their lower ends formed in a hookedmanner. The jaws are slidably received within the slots of the body formovement relative to the body with the locking sleeve. Further, thelifting clamp includes a compression spring within the body whichengages the upper ends of the jaws to bias the jaws radially outwardlyto maintain the hooked ends of the jaws in engagement with the inclinedsurfaces during movement of the locking sleeve and jaws relative to thebody and the compression spring biasing the locking sleeve toward itsforward position whereby the movement of the locking sleeve toward itsretracted position in opposition to the bias of the spring and towardits forward position with the bias of the spring effects expansion andcontraction, respectively, of the jaws. I

These and other objects of the invention will become more fully apparentfrom the following description and drawings wherein:

FIG. 1 is an axial cross-sectional view with portions shown in elevationof the lifting clamp of the present invention;

FIG. 2 is a cross-sectional view taken along lines 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 1 showing different parts of thelifting clamp of the present invention in different positions; and

FIG. 4 is a perspective of a part of the lifting clamp of the presentinvention. I

As representing a preferred embodiment of the present invention, thedrawings show a lifting clamp 10 which broadly comprises a hollowcylindrical body portion 12, a hollow cylindrical locking sleeve 14which is supported upon the body portion 12 in a concentric manner, aplurality of jaws l6, and a spring means 18 which serves to bias thejaws 16 in one direction.

Referring to FIGS. 1 and 2, the body portion 12 of the lifting clamp 10includes a hollow cylindrical portion 20 and an upper end portion 22.The hollow cylindrical portion 20 has an inner periphery 24 which withthe lower surface 26 of the upper end portion 22 defines a cylindricalinner chamber 28 therebetween which has an open end 30 at the lower mostportion of the hollow cylindrical portion 20. The hollow cylindricalportion 20 includes three axially extending and generally rectangularlyshaped through slots 31 therein which are circumferentially spacedapproximately apart. As previously stated, the slots 31 extend axially,as shown in FIG. 1, and terminate at their lower end in surfaces 34which are progressively tapered radially inwardly from the outerperiphery 35 and which terminate at the inner periphery at a positionimmediately adjacent the open end 30 of the inner chamber 28. Thecylindrical portion 20 also includes a radially outwardly extending lipor flange 36 which projects therefrom at a position immediately adjacentthe open end 30 of the inner chamber 28. The upper end portion 22 has athreaded axially extending aperture 38 which receives a complementarythreaded eyelet member 40 in order that the lifting clamp 10 can beattached to a suitable lifting device (not shown), such as a hydraulichoist.

The locking sleeve 14 is hollow, cylindrical, and shaped complementaryto the outer periphery 35 of the cylindrical portion 20 of the body 12and is slidably received thereon. The locking sleeve .14 is normally ina forward position in which its lower end 42 engages the radial lip 36of axis, body portion 12 and is in this manner supported upon the body12. The locking sleeve 14 also includes three radially extending slotsor openings 44 therethrough which are circumferentially spacedapproximately 120 apart. It should be noted that the locking sleeve 14is normally supported in a concentric manner upon the cylindricalportion 20 of the body 12 and is slidable thereon between a forwardposition, as

shown in FIG. 1, and a retracted position, as shown in FIG. 3.

Referring to FIGS. 1 and 4, the lifting clamp also includes three jaws16 which are generally elongated members having a rounded lower end .46with a projection or projecting portion 48 extending perpendicularlytherefrom to form a hooked end 50 for the purpose of grasping otherobjects. The jaws 16 have an upper end 52 with tangs or projectingportions 54 projecting perpendicularly therefrom and oppositely theprojections 48.'Further, the upper end 52 of each jaw 16 has a laterallyextending notch 56 opposite each tang 54 which defines a shoulder orseat 57. Each jaw 16 is slidably received within the slots 31 of thebody portion 12 and has its tang 54 received within one of the slots 44in the locking sleeve 14. The axial'length of the slots 31 is greaterthan the length of the jaws.

The spring means 18 can be any suitable type of spring and is hereinshown as a coiled compression spring 18 which is positioned within theinner chamber 28 of the body 12. The spring 18 is shown as having oneend in abutting engagement with the first surface 26 of the upper endportion22 of the body 12 and having its other end in abutting engagementwith the shoulder 57 of the jaws 16. In this manner, the spring 18maintains the tangs S4 of the jaws 16 within the holes 44 of the lockingsleeve 14 and biases the sleeve toward its forward position and therounded lower ends 46 of the jaws 16 into engagement with taperedsurfaces 34 of the body portion 12.

When it is desired to grasp an object 60, the locking sleeve 14 is thenmanually moved upwardly to its retracted position, as shown in FIG. 3,and the clamp is placed over an object 60 to be lifted. Because the jaws16 have their tangs 54 received within the holes 44 of the lockingsleeve 14, the jaws 16 are caused to move upwardly with the sleeve andwithin the slots 31 of the body 12. As the locking sleeve 14 is movedupwardly against the bias of the spring 18, the spring 18 maintains therounded end portion 46 of the jaws 16 in engagement with the taperedsurfaces 34 of the body portion 12. This results in the hooked ends 50of the jaws 16 being pivoted'radially outwardly into the slots 31 in thebody portion 12 and to expand their relationship between one another.When the opening between the hooked ends 50 of the jaws 16 is greaterthan the size of the object to be grasped 60, the lifting clamp 10 ismoved downwardly with the object 60 being received within the open end30 of the inner chamber 28.

Thereafter, the locking sleeve 14 is released and is moved downwardlywith respect to the body portion 12, as shown in FIGS. 1 and 2, by thespring means 18. The downward movement of locking sleeve 14 moves thejaws l6 downwardly within the slots 31 and the tapered surfaces 34 ofthe body portion 12 cause the hooked ends 50 of the jaws 16 to be movedradially inwardly by virtue of the engagement therebetween which ismaintained by the compression spring 18. The radially inward movement ofthe hooked ends 50 of the jaws 16 enables the jaws 16 to grasp theobject 60 and, thereafter, the object 60 can be lifted by operation ofthe lifting device (not shown).

The foregoing disclosure relates to only one embodiment of the inventionwhich may be modified within the scope of the appended claims.

What is claimed is:

1. A releasable clamp, comprising: a hollow cylindrical body portionhaving a plurality of elongated .cir-

cumferentially spaced slots therein, said slots terminat- 7 ing at oneend in inclined surfaces; a hollow cylindrical locking sleeve beingsupported upon said body in a concentric manner for sliding movementthereon in opposite directions and having a plurality ofcircumferentially spaced slots therein; a plurality of jaws having tangsreceived within said slots of said locking sleeve and being slidablyreceived within said slots of said body portion whereby said jaws aremovable with said locking sleeve; spring means for biasing said jawsradially outwardly into engagement with said inclined surfaces; saidlocking sleeve when respectively moved in opposite directions againstthe bias and with the bias of said spring means serving to expand andcontract said jaws, respectively.

2. A lifting clamp, comprising: a hollow cylindrical body portion havinga plurality of elongated circumferentially spaced slots therein, saidslots terminating at one end in inclined surfaces; a cylindricalouter-locking sleeve being supported upon and about said body in aconcentric manner for sliding movement thereon between forward andretracted positions; a plurality of jaws pivotally supported upon'saidlocking sleeve and being slidably received within said slots of saidbody portion whereby said jaws are moveable with said locking sleeve;and spring means for engagingly biasing said jaws radially outwardlyinto engagement with said inclined surfaces; said locking sleeve whenmoved toward its retracted position against the bias of said springmeans serving to expand said jaws and the bias of said spring meansmoving said locking sleeve when released toward its forward position inwhich said inclined surfaces engage and contract said jaws.

3. A lifting clamp, comprising: a hollow cylindrical body portion havinga plurality of axially extending and circumferentially spaced slotstherein, said slots terminating at a position adjacent one end of saidbody portion in inclined surfaces, said body portion having a radiallyoutwardly extending lip adjacent said one end of said body, said bodyhaving means for attaching said lifting clamp to a lifting device; ahollow cylindrical locking sleeve having one end engaging said lip ofsaid body and being supported thereby in a concentric manner upon saidbody for sliding movement thereon between forward and retractedpositions, said locking sleeve having a plurality of circumferentiallyspaced slots therein; a plurality of jaws slidably received within saidslots of said body for movement relative to said body with said lockingsleeve, said jaws having a tang and a notch at their upper ends, saidjaws having their lower ends formed in a hooked manner; a compressionspring within said body having one end engaged within said notches ofsaid jaws for biasing said jaws radially outwardly to maintain saidhooked ends in engagement with said inclined surfaces during movement ofsaid locking sleeve and jaws relative to said body and'for maintainingsaid tangs of said jaws within said holes of said locking sleeve andsaid compression spring for biasing said locking sleeve towardv itsforward position whereby movement of said locking sleeve to itsretracted position in opposition to the bias of said spring and to itsforward position with the bias of said spring effects expansion andcontraction, respectively, of said hooked ends of said jaws.

i l I!

1. A releasable clamp, comprising: a hollow cylindrical body portionhaving a plurality of elongated circumferentially spaced slots therein,said slots terminating at one end in inclined surfacEs; a hollowcylindrical locking sleeve being supported upon said body in aconcentric manner for sliding movement thereon in opposite directionsand having a plurality of circumferentially spaced slots therein; aplurality of jaws having tangs received within said slots of saidlocking sleeve and being slidably received within said slots of saidbody portion whereby said jaws are movable with said locking sleeve;spring means for biasing said jaws radially outwardly into engagementwith said inclined surfaces; said locking sleeve when respectively movedin opposite directions against the bias and with the bias of said springmeans serving to expand and contract said jaws, respectively.
 2. Alifting clamp, comprising: a hollow cylindrical body portion having aplurality of elongated circumferentially spaced slots therein, saidslots terminating at one end in inclined surfaces; a cylindrical outerlocking sleeve being supported upon and about said body in a concentricmanner for sliding movement thereon between forward and retractedpositions; a plurality of jaws pivotally supported upon said lockingsleeve and being slidably received within said slots of said bodyportion whereby said jaws are moveable with said locking sleeve; andspring means for engagingly biasing said jaws radially outwardly intoengagement with said inclined sur- faces; said locking sleeve when movedtoward its retracted position against the bias of said spring meansserving to expand said jaws and the bias of said spring means movingsaid locking sleeve when released toward its forward position in whichsaid inclined surfaces engage and contract said jaws.
 3. A liftingclamp, comprising: a hollow cylindrical body portion having a pluralityof axially extending and circumferentially spaced slots therein, saidslots terminating at a position adjacent one end of said body portion ininclined surfaces, said body portion having a radially outwardlyextending lip adjacent said one end of said body, said body having meansfor attaching said lifting clamp to a lifting device; a hollowcylindrical locking sleeve having one end engaging said lip of said bodyand being supported thereby in a concentric manner upon said body forsliding movement thereon between forward and retracted positions, saidlocking sleeve having a plurality of circumferentially spaced slotstherein; a plurality of jaws slidably received within said slots of saidbody for movement relative to said body with said locking sleeve, saidjaws having a tang and a notch at their upper ends, said jaws havingtheir lower ends formed in a hooked manner; a compression spring withinsaid body having one end engaged within said notches of said jaws forbiasing said jaws radially outwardly to maintain said hooked ends inengagement with said inclined surfaces during movement of said lockingsleeve and jaws relative to said body and for maintaining said tangs ofsaid jaws within said holes of said locking sleeve and said compressionspring for biasing said locking sleeve toward its forward positionwhereby movement of said locking sleeve to its retracted position inopposition to the bias of said spring and to its forward position withthe bias of said spring effects expansion and contraction, respectively,of said hooked ends of said jaws.